Hidden folder in Outlook (Pro Plus 2010)

I seem to have a "hidden" folder in my inbox some where. I have a folder called "Fullsail" which is not visible in the normal folders view. If I do a "Search all folders" it shows up in the search results in it's correct alphabetical position (i.e between a previous FU-- and a GD-- folder).

I've tried collapsing and expanding every folder and sub folder (using the little arrows on the left hand side of the folder view) in case I'd done an erroneous drag and drop into another folder, but it just doesn't show up.

This is driving me nuts. This is a corporate computer but I'm not sure my corporate IT would consider it a high priority case.